Helen Clark's UN dream fading

Former New Zealand Prime Minister Helen Clark is disappointed after being dealt another blow in the race to become the next Secretary-General of the United Nations.

Following the second ballot, Ms Clark reportedly dropped from sixth to seventh place out of a field of 12 candidates.

The former Labour Party leader tweeted her thanks to supporters following the result, saying she will be discussing the outcome over the coming days.

Former Portuguese Prime Minister Antonio Guterres is still the frontrunner to be the next Secretary-General after receiving 11 votes in favour from the 15-member council.

The Security Council will continue to hold secret ballots until a consensus is reached on a candidate to replace UN chief Ban Ki-moon, who steps down at the end of 2016 after his second five-year term.

It is expected that an election will take place in September or October.

This latest poll follows the controversial news that Australia Prime Minister Malcolm Turnball declined to endorse his Labour predecessor, Kevin Rudd, who had hoped to run for the top job.